Reapply an improved version of r180816/180817.

Change the informal convention of DBG_VALUE machine instructions so that
we can express a register-indirect address with an offset of 0.
The old convention was that a DBG_VALUE is a register-indirect value if
the offset (operand 1) is nonzero. The new convention is that a DBG_VALUE
is register-indirect if the first operand is a register and the second
operand is an immediate. For plain register values the combination reg,
reg is used. MachineInstrBuilder::BuildMI knows how to build the new
DBG_VALUES.

rdar://problem/13658587

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185966 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 10 deletions

diff --git a/lib/CodeGen/LiveDebugVariables.cpp b/lib/CodeGen/LiveDebugVariables.cpp
index 5837f0cccb..85bed46569 100644
--- a/lib/CodeGen/LiveDebugVariables.cpp
+++ b/lib/CodeGen/LiveDebugVariables.cpp
@@ -108,6 +108,7 @@ class LDVImpl;
 class UserValue {
   const MDNode *variable; ///< The debug info variable we are part of.
   unsigned offset;        ///< Byte offset into variable.
+  bool IsIndirect;        ///< true if this is a register-indirect+offset value.
   DebugLoc dl;            ///< The debug location for the variable. This is
                           ///< used by dwarf writer to find lexical scope.
   UserValue *leader;      ///< Equivalence class leader.
@@ -134,9 +135,10 @@ class UserValue {
 
 public:
   /// UserValue - Create a new UserValue.
-  UserValue(const MDNode *var, unsigned o, DebugLoc L,
+  UserValue(const MDNode *var, unsigned o, bool i, DebugLoc L,
             LocMap::Allocator &alloc)
-    : variable(var), offset(o), dl(L), leader(this), next(0), locInts(alloc)
+    : variable(var), offset(o), IsIndirect(i), dl(L), leader(this),
+      next(0), locInts(alloc)
   {}
 
   /// getLeader - Get the leader of this value's equivalence class.
@@ -299,7 +301,8 @@ class LDVImpl {
   UVMap userVarMap;
 
   /// getUserValue - Find or create a UserValue.
-  UserValue *getUserValue(const MDNode *Var, unsigned Offset, DebugLoc DL);
+  UserValue *getUserValue(const MDNode *Var, unsigned Offset,
+                          bool IsIndirect, DebugLoc DL);
 
   /// lookupVirtReg - Find the EC leader for VirtReg or null.
   UserValue *lookupVirtReg(unsigned VirtReg);
@@ -414,7 +417,7 @@ void UserValue::mapVirtRegs(LDVImpl *LDV) {
 }
 
 UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset,
-                                 DebugLoc DL) {
+                                 bool IsIndirect, DebugLoc DL) {
   UserValue *&Leader = userVarMap[Var];
   if (Leader) {
     UserValue *UV = Leader->getLeader();
@@ -424,7 +427,7 @@ UserValue *LDVImpl::getUserValue(const MDNode *Var, unsigned Offset,
         return UV;
   }
 
-  UserValue *UV = new UserValue(Var, Offset, DL, allocator);
+  UserValue *UV = new UserValue(Var, Offset, IsIndirect, DL, allocator);
   userValues.push_back(UV);
   Leader = UserValue::merge(Leader, UV);
   return UV;
@@ -445,15 +448,17 @@ UserValue *LDVImpl::lookupVirtReg(unsigned VirtReg) {
 bool LDVImpl::handleDebugValue(MachineInstr *MI, SlotIndex Idx) {
   // DBG_VALUE loc, offset, variable
   if (MI->getNumOperands() != 3 ||
-      !MI->getOperand(1).isImm() || !MI->getOperand(2).isMetadata()) {
+      !(MI->getOperand(1).isReg() || MI->getOperand(1).isImm()) ||
+      !MI->getOperand(2).isMetadata()) {
     DEBUG(dbgs() << "Can't handle " << *MI);
     return false;
   }
 
   // Get or create the UserValue for (variable,offset).
-  unsigned Offset = MI->getOperand(1).getImm();
+  bool IsIndirect = MI->getOperand(1).isImm();
+  unsigned Offset = IsIndirect ? MI->getOperand(1).getImm() : 0;
   const MDNode *Var = MI->getOperand(2).getMetadata();
-  UserValue *UV = getUserValue(Var, Offset, MI->getDebugLoc());
+  UserValue *UV = getUserValue(Var, Offset, IsIndirect, MI->getDebugLoc());
   UV->addDef(Idx, MI->getOperand(0));
   return true;
 }
@@ -921,8 +926,12 @@ void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
   MachineOperand &Loc = locations[LocNo];
   ++NumInsertedDebugValues;
 
-  BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
-    .addOperand(Loc).addImm(offset).addMetadata(variable);
+  if (Loc.isReg())
+    BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
+            IsIndirect, Loc.getReg(), offset, variable);
+  else
+    BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
+      .addOperand(Loc).addImm(offset).addMetadata(variable);
 }
 
 void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,